The invention relates to a ratchet wrench for rotating threaded fasteners and in particular threaded fasteners located in areas having obstructions or limited access to the fastener to be rotated.
In the relevant art, various hand tools or wrenches are provided for turning of fasteners such as threaded nuts, bolts or pipes. In particular, those wrenches associated with turning a nut or bolt generally rely on a hexagonal shaped head and may be characterized as an open-end wrench which generally engages the fastener on two parallel surfaces of the hexagon head, or a closed-end wrench which engages the fastener on all six corners of the hexagon. The closed-end wrench may have either a hexagonal or dodecahedral configuration. The hexagonal configuration has the advantages of being the same hexagonal shape as the fastener which provides the greatest contact surface areas for transferring rotational forces from the wrench to the fastener, thus reducing the likelihood of slippage from the fastener. However, the hexagonal configuration limits the available engagement geometries with the fastener which is particularly troublesome when attempting to rotate a fastener in a tight or obstructed location. A dodecahedral configuration provides twelve angled surfaces for engagement with the fastener, thus improving the available engagement geometries but reduces the contact surface areas with the fastener allowing for more likelihood of slippage from the fastener.
A further characteristic of the open-end wrench is that it may engage the fastener from either the side or top. However, the closed-end wrench must engage the fastener from the top. If the fastener is on a long continuous shaft, such as a long bolt, stud, or a length of threaded pipe, access to the top of the fastener is restricted and the closed-end wrench may be unable to engage the fastener, or in the alternative, engaging the fastener may involve moving the wrench such a distance along the stud or pipe as to make its use impractical. In these cases, the open-end wrench has an advantage in accessing the fastener. The open-end wrench however has the disadvantage of limited engagement of the fastener, and due to varying tolerances in fastener size, it is known for open-end wrenches to damage the corners of the hexagon, and perhaps cause injury to the wrench user, by xe2x80x9cslipping,xe2x80x9d especially if the fastener is difficult to turn.
A variation of the closed-end wrench, commonly called a flare nut wrench, is essentially a closed-end wrench with a small opening in the end that allows slipping the wrench over tubing or a threaded stud to engage the fastener. Due to the opening, these wrenches can slip and cause damage to the fastener or injure the wrench user. In addition, flare nut wrenches require clearances around the fastener to allow for positioning of the wrench with the fastener which limits the usefulness of the flare nut wrench in tight or obstructed locations.
Several inventions have attempted to combine the complete fastener engagement advantages of the closed-end wrench with the side engagement advantages of the open-end wrench. U.S. Pat. No. 2,758,493 (Goldwater) teaches a reversible ratchet wrench that engages a fastener on the side and provides a six point engagement of the fastener.
U.S. Pat. No. 5,113,726 (Ethridge) teaches a pipe fastener tool that also provides a side six point fastener engagement. U.S. Pat. No. 6,263,765 (McCamley) shows another wrench capable of side six point fastener engagement. U.S. Pat. No. 6,279,427 (Francis) shows a hydraulically operated torque wrench designed for side twelve point fastener engagement.
Each of these inventions provides a solution to turning a fastener on a continuous shaft that is useful in some applications. However, all of these inventions require manipulation of the head of the wrench mechanism at a location in proximity to the fastener, and therefore cannot be used in situations where access to the fastener is so restricted that the fastener is not readily accessible to the hands of the user.
Therefore, what is highly desirable is a simple tool whose actuator assembly is operated remotely from the fastener in situations where access to the fastener on a continuous stud, bolt or pipe is restricted and further includes a narrow profile so that it may be used in tight or obstructed locations.
Objects and Advantages
One object of this invention is to provide a tool to turn a fastener that engages fasteners that are on a threaded stud or pipe.
A second object of this invention is to provide a tool to turn a fastener that provides either a six or twelve point engagement of the fastener.
A third object of this invention is to provide a tool to turn a fastener that engages a fastener in a restricted access location where the fastener cannot be reached by the user""s hands.
A fourth object of this invention is to provide a tool to turn a fastener that will access the fastener in a confined space of approximately the width of the fastener.
A fifth object of this invention is to provide a tool to turn a fastener that is adaptable to a variety of turning aids.
A sixth object of this invention is to provide a tool to turn a fastener that is sturdily and simply constructed so as to provide long tool life.
A seventh object of this invention is to provide a tool to turn a fastener that is economical to manufacture.
The invention comprises a ratchet wrench for turning a fastener in a tight or obstructed location. The wrench is manufactured to have a narrow profile equal to or less than that of a fastener in which the wrench is intended to be used upon. The narrow profile allows the wrench to be used in locations having restricted access or obstructions. The thickness of the body of the wrench in relation to either the body""s width or length defines the narrow profile. The thickness of the body is such that it is considerably smaller than either the width or length which allows the body of the wrench to fit in tight or obstructed locations.
The wrench includes a fixed jaw which is incorporated into a front end of a body of the wrench. Another movable upper jaw is pivotally attached to the body of the wrench and is further coupled to an actuator assembly. The actuator assembly is operable from a position away from the movable and fixed jaws. The movable and fixed jaws are arranged in opposition and define between themselves a substantially equal regular polygon shaped opening for engaging the fastener. The regular polygon shaped opening may be in the form of a hexagon or dodecahedron. The body of the wrench includes a receptacle for attaching a handle such as a breaker bar, standard ratchet wrench or extension bar. In one embodiment of the invention, the handle is attached perpendicular to the body of the wrench. In another embodiment of the invention the handle is attached in parallel to the body of the wrench.
In both embodiments of the invention, the drive receptacle is situated along a longitudinal center axis of the body of the wrench.
The wrench includes an opening side for situating the fastener between the movable and fixed jaws which is approximately centered along one side of the regular polygon shaped opening. A pivoting side is provided for attaching the movable upper jaw to the wrench body and is positioned on the opposite side of the regular polygon shaped opening in parallel to the opening side. The movable upper jaw is pivotally attached to the body of the wrench with a fastener means such as a pin, rivet, or bolt.
An actuator assembly is provided for operating the wrench remotely, away from the movable and fixed jaws and includes a guide extending laterally from the pivoting side for slideably maintaining the actuator shaft adjacent to and generally in parallel with the pivoting side. A second pivotal fastener is provided for pivotally fastening the actuator shaft to the movable upper jaw. The actuator shaft is pivotally attached to the movable upper jaw with a fastener means such as a pin, rivet, or bolt.
The actuator shaft provides the means for slideably transmitting an opening and a closing force to the movable upper jaw during operation. A coil or torsion spring coupled to the actuator shaft is used to provide a closing bias force to the movable upper jaw. The closing force bias may be adjusted by moving a spring stop longitudinally along the actuator shaft in order to obtain a desired closing bias force. The closing bias force is intended to provide sufficient force to allow an user to tighten a fastener until snug against another surface. If the closing bias force is exceeded, the movable upper jaw is allowed to perform a ratcheting action.